Unfortunately it has implications for all us long time meditators too.

I'm one of those who is convinced that many of the 'wondrous' experiences reported by practioners of breath meditation are related to hypoxic and hyperoxic induced nuerological states. If hypoxia is involved then some us may be facing a previously unknown downside.

Nik

http://www.newscientist.com/channel/health/mg19225795.600-too-little-oxygen-may-prompt-onset-of-alzheimers.html

Too little oxygen may prompt onset of Alzheimer's

THE many disparate risk factors for Alzheimer's disease may be linked by an underlying common cause. It has been known that diabetes, strokes, clogged arteries and plain old ageing increase the risk of developing Alzheimer's, with only 5 per cent of cases strongly influenced by genes. Now evidence has emerged that lack of oxygen is the root cause.

Weihong Song at the University of British Columbia in Vancouver, Canada, and his colleagues took mice engineered to develop Alzheimer's-like plaques and put them in a hypoxia chamber for one month, where for 16 hours each day they got less than 40 per cent of the oxygen they needed. Six months later, the oxygen-deprived mice had developed twice as many beta-amyloid plaques - the hallmark of the disease - as similar mice kept in normal conditions. The plaques were also larger and the hypoxic mice performed worse on memory tests.

Beta-amyloid is formed when a gene known as BACE1 produces an enzyme that cuts long strands of harmless amyloid protein into small and potentially plaque-forming pieces. Song's team found that oxygen deprivation triggers an upregulation of BACE1 (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0606298103). More beta-amyloid means more plaques, and in turn, more neuron death. Getting enough oxygen to the brain may help stave off Alzheimer's in people with known risk factors, says Song, adding that vasodilators, which enlarge the blood vessels, may help.